High resolution ink-jet printing on edibles and products made

ABSTRACT

Disclosed are methods of printing high resolution images on edible substrates with dispersed pigmented inks using a drop-on-demand ink-jet printer. Dispersed pigmented white inks useful with the inventive methods are also disclosed. White images having a resolution greater than 200 dpi can be printed on chocolate using the methods and inks disclosed herein. The inventive methods and inks may also be integrated with a consumer-driven site vending or e-commerce application in which the consumer provides the image to be printed and edibles bearing the printed image are prepared for rapid turnaround.

This application is a divisional of U.S. patent application Ser. No.09/587,108, filed Jun. 2, 2000, which is incorporated by reference inits entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to high resolution printing on edibles usingan ink-jet printer and dispersed pigmented inks. The system provides forrapid turnaround from image input to printed edible product. Methods ofprinting, ink formulations suitable for use with the methods,site-vending and e-commerce applications are all described herein, andare within the intended scope of the invention.

2. Description of the Related Art

Highly detailed images can be formed on chocolates using a pad printingprocess. In this process, the substrate is contacted with an inked padhaving the image formed thereon. Sometimes, in order to prepare an imagehaving greater resolution, the chocolate is contacted repeatedly withthe pad. An example of a pad printing process is described in CA2,057,985. While, the pad printing process can deliver highly detailedimages it cannot be adapted for rapid turnaround applications. Eachrequested change to an image requires that a corresponding change bemade to the printing pad or the manufacture of a new pad which meansthat pad printing will have a slow turnaround time. One object of theinvention, therefore, is to provide for rapid turnaround printing ofhigh resolution images on edibles.

Ink-jet printing systems are generally of two types: continuous jet anddrop-on-demand. In continuous jet ink-jet systems, ink is emitted in acontinuous stream under pressure through at least one nozzle. The streamis broken up into droplets at a fixed distance from the orifice.Typically, the ink droplets in continuous ink-jet systems are formed bya piezoelectric crystal, which is vibrated at controlled frequencyadjacent to the ink stream. To control the flow of ink droplets, theseinks are charged (by addition of salts and other conductive agents) andrelayed in accordance with digital data signals. The droplets are passedthrough an electrostatic field, which adjusts the trajectory of eachdroplet. The droplets are either directed back to a gutter forrecirculation or to a specific location on the substrate to created thedesired character matrix.

In drop-on-demand systems, a droplet is expelled under pressure from avalve directly to a position on the substrate in accordance with thedigital data signals. A droplet is not formed or expelled unless it isto be jetted to the substrate. The formation of droplets in drop-ondemand systems can either be achieved by a piezoelectric crystal(similar to continuous jet systems) or by a thermal (bubble-jet)technique. The latter technique involves formation of ink droplets bythermally heating ink in the cartridge reservoir thereby forcing ink tobe expelled in an “on-demand” basis. Typically, drop-on-demand systemsprint at a slower rate than continuous jet systems (due to time requiredto make droplets on demand) but produce higher resolution images.However, some of the commercially available printhead units (forexample, manufactured by Xaar, Trident and Picojet) achieve highthroughput rates even with drop-on-demand systems by using theirproprietary technologies. Also, since drop-on-demand systems require noink recovery, charging, or deflection, these systems are simpler thanthe continuous stream systems.

Further, continuous jet ink-jet printing systems do not yield the samehigh resolution images that can be obtained with drop-on-demand ink-jetsystems. A typical maximum resolution for a continuous jet printer imageon an edible substrate using a single printhead and a single passprinting is about 70-90 dpi.

Published European Patent Application EP 705 890 A1 discloses an ink foruse with a continuous ink jet printer. The ink comprises pigment, suchas titanium dioxide; binder, such as shellac orpoly(1-vinyl-2-pyrrolidone); and an aqueous carrier. The binder isapparently required to increase the compatibility of the inked imagewith the substrate in the continuous ink-jet environment contemplated.

Other methods of decorating edibles are known in the prior art. UKPatent GB 2,291,838 B describes a machine and method for printing on anedible substrate. This patent discloses a generic ink-jet/bubble-jethead assembly together with a stepping motor for moving the headassembly. A pump provides food coloring to the head assembly from inkreservoirs. A computer provides the instructions for printing on theedible substrate.

Food colorings which are dye-based systems behave differently thandispersed pigmented inks in an ink-jet environment, and exhibitprofoundly different image characteristics on edible substrates.Dye-based inks possess limited opacity and therefore do not hide darkbackgrounds colors, such as milk chocolate and dark chocolate surfaces.Also, dye-based inks are not available in all colors. For example, whiteink is not available as a dye system but is available only as apigmented (dispersed) system.

The examples of the prior art do not describe methods or systems toprint high resolution images on edibles using an ink-jet printer andpigmented inks. There is also no description of a system or methodwherein a consumer can participate in the selection and customization ofan edible product with a high resolution image and subsequently receivethe customized product in rapid fashion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram showing the elements of a system forpreparing edibles having high resolution images ink-jet printed thereon.

FIG. 1B is a block diagram of a manufacturing subsystem of the system ofFIG. 1A.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a customizable process forpreparing edibles having high resolution images that have been selectedby a consumer ink-jet printed thereon according to the invention thatcomprises the steps of: selecting digital image information; processingthe digital image information to form processed digital imageinformation; ink-jet printing an image corresponding to the processeddigital image information using dispersed pigmented ink; wherein saidstep of selecting digital image information is performed by anindividual consumer.

The input of the individual consumer is a key component of thecustomizable process according to this embodiment of the invention.Rapid turnaround from the consumer's selection of digital imageinformation to finished product having high resolution images printedthereon makes possible the consumer's involvement in the manufacture ofpersonalized products.

In preferred embodiments, the above system for preparing edibles havinghigh-resolution, consumer selected images printed thereon, is embodiedin connection with a rapid-turnaround site-vending or e-commerceapplication. In these embodiments, the consumer selects digital imageinformation, at a vending site or over the internet, for example. Theinformation is processed, remotely or on-site, and printed onto anedible substrate with an ink-jet printer using the dispersed pigmentfood grade inks of the invention. The entire process is accomplishedaccording to consumer selections with rapid turnaround. In someembodiments, the turnaround can be on an as-you-wait basis.

It is a further object of the invention to provide a process forprinting high resolution images on an edible substrate comprising thesteps of: (a) providing digital image information; (b) processing thedigital image information to prepare processed digital imageinformation; and (c) printing an image from the processed digital imageinformation on an edible substrate with a drop on demand ink-jet printerusing dispersed pigment food-grade ink to obtain a printed image havingresolution greater than 200 dpi. Significantly, the image resolution (asmeasured in dots per square inch, (dpi)) achieved using the process ofthis invention may be obtained even using a single printhead and singlepass printing. Of course, the invention set forth herein is not limitedto a single printhead or single pass printing, but also includes the useof multiple printheads and/or multiple pass printing.

It is a further object of the invention to provide a system forpreparing edibles having high-resolution, consumer-selected, dispersedpigmented ink images printed thereon with an ink-jet printer,comprising: a digital image information selection device incommunication with an image processor for producing processed digitalimage information and an ink-jet printer adapted to print a highresolution image corresponding to said processed digital imageinformation on an edible substrate.

It is also an object of the invention to provide novel edible dispersedpigmented ink compositions which can be used in drop on demand ink jetsystems to deliver high resolution images.

Novel edible, ink-jettable ink compositions according to the inventioncomprise: a food-grade white pigment, a dispersant, an alcohol, andwater.

In a particular embodiment, the present invention comprises afood-grade, drop-on-demand ink jettable ink consisting essentially of:titanium dioxide, glycerine and/or propylene glycol and/or polypropyleneglycols, a lower alcohol, water, and optionally a surfactant. In apreferred embodiment, the ink is substantially free of binder.

It is also an object of the invention to provide high resolution imageson edible substrates with dispersed pigmented inks printed with drop-ondemand ink-jet technology. Particularly preferred embodiments accordingto the invention include white ink images having a resolution greaterthan 200 dpi, and more preferably between 300 and 1200 dpi, printed withdrop-on demand ink-jet technology on chocolate substrates.

In a particular embodiment, novel high resolution printed edibleproducts are described, wherein a printed image is printed on a surfacewith localized three dimensional (3-D) features, for example anirregular or uneven surface.

It is a further object of the invention to provide a computer-readablemedium storing executable code adapted to control a server computer on anetwork to perform a method for facilitating custom manufacturing of adecorated edible item on the basis of instructions of a user. The methodincludes communicating over the network with a client computer of theuser, receiving over the network, from the client computer, imageinformation submitted to the client computer by the user, andcommunicating the received image information to an ink-jet printer tocause printing on an edible item of a high quality image thatcorresponds with the received image information.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An important motivation behind the use of ink jet printing is that thistype of printing allows rapid turnaround from the selection of an imageto the printing of edibles bearing the selected image. The rapidturnaround enabled by the use of ink-jet printing (as opposed to padprinting) permits a consumer to dictate the steps of digital imageinformation selection and image processing. The rapid-turnaround,consumer-centered approach to printing on edibles permits theintroduction of applications heretofore not deemed possible, or ifpossible, impractical.

In some embodiments, the present invention comprises a system forpreparing edibles having high-resolution, consumer-selected and/orconsumer-provided images printed thereon. The consumer's involvement inthe preparation of an individualized edible is a key component of theseembodiments of the invention. Thus, in the system, a digital imageselection device is consumer-driven.

The process for printing high resolution images on an edible substrateaccording to the invention comprises, in the first instance, the step ofproviding digital image information. The source of the digital imageinformation is not particularly limited. Digital image information foruse with the printing process of the present invention may be in theform of an electronic file (on disk or otherwise), or may be transmittedfrom a source. Providing digital image information may be accomplished,for example, with a keyboard, a digital camera, a scanner, a digitalvideo camera, or the image may be provided in pre-recorded image format.Presently available technology includes many sources of digital imageinformation that would be known to those of ordinary skill in the art,and which could be readily used in the step of providing digital imageinformation.

Digital information must be in communication with the image processor.Communication may be effected over the Internet, by a computer, throughcomputer cables, wiring, fiber optic cabling, or other means throughwhich digital image information can be transmitted. Specificallycontemplated herein is an embodiment wherein a digital image informationselection device is incorporated with the image processor. For example,a digital camera typically includes options for processing an image. Inthis situation, the digital image information selection device is saidto be in communication with the image processor. Likewise, when digitalimage information is captured by a digital image information selectiondevice and placed on a storage medium, and thereafter the digital imageinformation is loaded into a software package for processing the image,the digital image information selection device is said to be incommunication with the image processor. Similarly, when digital imageinformation is received over the Internet by the server functionality ofthe present invention, this will constitute the communication. Thestructural details of these programs or communicating devices are wellknown.

In preferred embodiments, the digital image information is providedunder the direction or control of individual consumers. A site-vendingapplication can include an area, such as a kiosk, where the consumer isprovided with a digital camera, keyboard, computer terminal or the liketo prepare individualized digital image information. Of course, any typeof device capable of providing digital image information, such aspersonalized messages, sentiments or a clip-art image selected by theconsumer from a library of such images may be used. The digital imageinformation may be then processed at the site and printed on an ediblesubstrate, such as chocolate, on an as-you-wait basis.

In a preferred embodiment, consumers provide individualized digitalimage information at a computer which is linked on-line to the internet.In either the site vending or internet embodiments of the presentinvention, there is rapid turnaround between the consumer's selection ofdigital information and obtaining edibles printed with the selectedimages.

In a particularly preferred embodiment of the present invention, thesystem utilizes a wide area network (WAN) such as the Internet toreceive custom orders from consumers for designs to be printed on theedible items. The system preferably includes an Internet (TCP/IPcompliant) server that interacts with consumer client computers usingthe client computer's graphical user interface (GUI). The interface withthe consumer preferably allows the consumers to interactively peruseoptions for decoration of edibles, and more preferably, the ability topreview what the final product will look like. The above functionalityis preferably achieved using a combination of server side applications,such as common gateway interface programs (CGI), for allowing the serverto accept search terms and interface with databases, and client sideapplets, such as Java applets, or the like, which execute in clientbrowser software.

A preferred implementation of the consumer customized manufacturingsystem of this present invention is illustrated in block diagram form inFIG. 1A. In that figure, consumers operating client computers 1 areconnected to a wide area network (WAN) such as the Internet. Suchconnection can be direct or via an Internet service provider (notshown). The client computers 1 each preferably include communicationshardware and an operating system with graphical user interface (GUI)functionality to allow for interface with the Internet. Each clientcomputer preferably has graphical World Wide Web (Web) browser software,such as Netscape Navigator or Microsoft Internet Explorer, loadedthereon operable to read and send Hypertext Markup Language (HTML) formsfrom and to an Hypertext Transport Protocol (HTTP) server on the Web.The client computer 1 preferably is operable to act as a virtual machineto run Java applets, or the like, downloaded by the browser from theserver.

Server/host computer system 2 receives information from consumer clientcomputers 1 over the Internet. The server/host computer system 2preferably includes hardware, HTTP compliant software, an operatingsystem and common gateway interface (CGI) software for interfacing withinput queries and sources of data.

Manufacturing subsystem 3, to be described in more detail below,includes the hardware and software necessary to interface with theserver/host computer system 2 and to use the input information to custommanufacture decorated edible items. On site data entry 4 allows on siteentry by consumers of custom orders as an alternative to receipt of thisinformation over the Internet.

A preferred implementation of manufacturing subsystem 3 is illustratedin block diagram form in FIG. 1B. Central Processing Unit (CPU) 10 is acomputer having the functionality to run software programs, communicatewith outside sources of date, and control peripheral devices.Preferably, the CPU 10 is operable to configure data for graphicaldisplay from input data received from server/host computer system 2 andon site data entry 4, as well as from graphical data files stored instorage device 30, or RAM 20. A user can interface with the CPU 10 usingkeyboard 40 and/or mouse 45, preferably using a GUI operating system.Printer 60 is used to decorate the edible items under the control of theCPU 10 based upon the graphical data. Prior to printing, the graphicaldata may be subjected to modification by the user of the CPU 10, ifnecessary, by using the keyboard 40 and/or mouse 45 in conjunction withthe GUI.

In operation, in the Internet implementation, a consumer typically wouldtype in a Uniform Resource Locator (URL) of the server/host computersystem 2 and receive from the server/host computer system 2 aninteractive form, such as an HTML document, as well as any Java applets,or the like, necessary to allow the consumer to view and submit his orher options for customizing the decoration of the edible items. Theapplets and CGI programs do verifications to ensure, for example, theconsumer does not chose too large a decoration for the edible. Assumingthe consumer request is within appropriate limits, the server acts as anintermediary to pass the requested information along to themanufacturing subsystem for actual printing under the control of CPU 10.

An example of the integrated system of the present invention includes amethod in which the consumer selects digital image information whileon-line. The consumer selects digital image information by entering fromthe keyboard, selecting from a library of images, inputting a digitalphotograph, remotely controlling the taking of a live digital photographor video image, or other mode available on-line. The consumer thencommunicates, by conventional Internet interfacing techniques, theselected digital image information through server/host computer system2, to remote image processing functionality operating in CPU 10.

Alternatively, the consumer may simply invoke an image processor whileon-line and communicate, in real time, the digital image information toa program for processing an image. Thus, the step of processing thedigital image information to produce processed digital image informationdoes not have to be done remotely, but may be accomplished while theconsumer is on-line, and under the interactive, real time supervision ofthe consumer. After the digital image information has been communicatedto the image processing functionality of CPU 10, and processed digitalimage information has been produced, the processed digital imageinformation is transmitted to an ink-jet printer for printing on anedible substrate.

The server/host computer system 2 and on site data entry 4, preferably,in addition to communicating to the manufacturing subsystem,communicates with a financial computer of the system to utilize inputcustomer credit card information or the like for payment for the customdecorated edible items. Further, the server/host computer system 2 andon site data entry 4, preferably, in addition to communicating to themanufacturing subsystem and the financial computer of the system, alsocommunicates with an inventory management computer system to coordinatethe rapid fulfillment of the customer order through timely shipment ofthe customized product.

In some circumstances, the consumer may be involved in the step ofprocessing the digital image information by changing visual parameters,such as colors, tones, brightness, contrast, or the size and aspectratio of the image, or by cutting-and-pasting or merging images, and thelike.

If the digital image information is provided over the Internet,software, in the form of Java applets, or the like, for processing theimage on the consumer's client computer can be provided on-line.Alternatively, the consumer may be provided with an image processor fordigitally processing the image at the site where the digital imageinformation is provided, for example at on-site data entry 4. Softwarepackages for processing digital image information are known, and theinvention is not particularly limited in this regard.

An image processor is, generally speaking, a software package thatpermits sophisticated alteration of digital image information. Asindicated above such programs are known in the art. Commerciallyavailable programs that may serve as image processors include, withoutlimitation, Adobe Photoshop and Microsoft Photo Editor. Less involvedimage processors are contemplated, and might include, withoutlimitation, standard picture controls available on a digital stillcamera or digital video camera.

Certain sub-steps involved in the step of processing the digital imageinformation may be “invisible” to the consumer, notwithstanding how theimage is provided. By “invisible” in this context is meant that certainsub-steps of image processing will likely take place without the directinvolvement of the consumer. This is because certain image processingsteps are known from experience to be suitable for particularsubstrates, such as taking the negative of an image to be printed inwhite on chocolate, and these steps would not be expected to be readilyapparent to the consumer. Likewise, in some instances it may bedesirable to resolve the digital image information into a series ofimages that are printed on top of one another to create a higherresolution image. This sub-step of resolving the image into a series ofimage layers is the type of sub-step that might be “invisible” to theconsumer.

In a preferred embodiment[s], the digital information selection deviceis provided at the same site where the image processor and the ink-jetprinter are located. This type of embodiment can be referred to as asite-vending application, where the consumer selects digital imageinformation, optionally participates in the processing of the digitalimage, and then waits while an edible bearing the selectedhigh-resolution image is produced. Of course, the turnaround need not beon an as-you-wait basis. The consumer may place an order and return forit. Nevertheless, rapid turnaround of individually customized edibles iscontemplated using the systems, processes and inks according to theinvention.

In a particularly preferred embodiment, the digital informationselection device, image processor, and the ink-jet printer areintegrated in a single portable apparatus. For example, a portableapparatus would find application with photographers taking photographsat special occasions such as weddings, reunions, etc. The rapidturnaround capability of the invention would allow the capturing ofimages of the participants of the occasion and the delivery ofconfectionery products with their images while they are still at theoccasion.

While the preferred embodiments have been described above in relation todigital image selection via software running on a consumer's clientcomputer 1, or via on-site data entry 4, the digital image informationselection device of the present invention is not limited to theillustrated embodiments. Examples of such selection devices for useon-site may include a keyboard or computer terminal, a live video cameraimage acquisition device, a digital still camera image acquisitiondevice, a scanner, a reader for reading digital information, or anyother type of device for supplying digital image information known inthe art.

The step of printing an image on an edible substrate according to theinvention utilizes printer 60, an apparatus that may be described as aconventional ink-jet printing apparatus modified to operate using theedible ink of this invention and modified to print on the ediblesubstrates of the invention. The preferred ink-jet printing apparatus isa drop-on-demand ink-jet printing apparatus, comprising a cartridge forholding ink which is integrated with a print head for printing on thesubstrate. The apparatus comprises a driver for driving the print headaccording to instructions corresponding to the processed digital imageinformation received. The apparatus typically comprises a conveyer forcausing relative motion between the substrate and the print-head.

Once the digital image information has been provided, the image isprocessed to prepare processed digital image information. Thisinformation is then communicated to the printer in appropriate form toenable the printer to produce the high resolution printed image on theedible product. Of course, edible substrates come in a variety ofcolors, and printed images will have to be processed at least so that aprinted image has the appropriate intensity and contrast for thebackground color of the substrate. In a preferred embodiment, theprinted image comprises white ink, and the substrate is chocolate. Inthis situation, the step of processing an image, for example a digitalphotograph or the like, will involve taking the “negative” of thedigital image information, and enhancing image brightness and contrastprior to printing. This can be accomplished, for example, using an imageprocessor such as Adobe Photoshop.

Dispersed pigmented white ink, which is discussed in more detail below,is provided to the “black” reservoir or cartridge of a black-onlyink-jet printer. Obviously, if a non-white single color image isdesired, a pigment based ink containing a dye would be provided to the“black” reservoir of the cartridge. If a printer with a color inkcartridge is utilized, white ink will be provided to the black reservoirand “colored” pigment based inks will be provided to the remainingreservoirs. The particular arrangement of the reservoirs is notparticularly critical. It is advisable to sonicate (i.e. ultrasonicallymix) the cartridge to effect dispersion of the pigments in the ink priorto printing and intermittently to prevent the nozzle from becomingclogged.

Once the printer is loaded with ink, the edible substrate is held andconveyed past the print-head (or vice versa). The edible substrate isnot particularly limited. In a preferred embodiment, the substrate is aconfectionery product. The substrate may be for example, chocolate,cookies, M&M®s-type candy or other sugar shell candy, or hard candy,jellybeans, starch-based, savory snacks, and gelatin-based gummi andsoft candies. Even ice creams and pet food are within the scope of theinvention. In a preferred embodiment, the substrate is a predominantlyplanar chocolate tablet.

Other embodiments of image processing according to the inventioninclude, controlling the intensity of the brightest area of an image,electronically separating an image such that it can be printed inmultiple applications of ink (i.e., multi-pass through printer),brightness equalization across the printed area, and sectional controlof image brightness and contrast.

Printing on a substrate such as chocolate presents special challenges inobtaining a high quality high resolution image. The use of techniquesdescribed above have been discovered to address many of the challenges.For example, when printing using ink-jet technology onto chocolate, thecompatibility of the ink with the surface is critical. The surfacechemistry of the chocolate surface and that of the ink will determinethe behavior to the ink droplets once they have been jetted onto thesurface. By controlling the maximum level of brightness for an image, itis possible to ensure that too much ink is not jetted into a givensection of a printed image. When this occurs, the ink droplets may tendto coalesce into larger droplets before the ink has had sufficient timeto completely dry. This leads to a loss of resolution for the affectedsection of the image.

Another embodiment is to “separate the image into layers” such that theprinting of the complete image is completed by multiple applications ofink. This allows sufficient time for the successive ink applications todry before another application is made. This allows a larger totalapplication of ink and thus brighter images while avoiding loss orresolution due to coalescence of printed droplets.

Another embodiment utilizes an approach of brightness equalizationacross the printed area. By adjusting the contrast and shading of thelight and dark areas of an image, it is possible to enhance the overallquality of the image on a chocolate surface. This technique tends tominimize extremes of darkness or brightness and results in an improvedimage quality for images with very severe contrasts.

Another embodiment is to control the brightness of an image in certainsections of an image rather than of the image as a whole. Here again,the image quality and resolution will be enhanced by avoidingcoalescence problems in very bright areas of the image.

These techniques will generally allow more difficult images to beprinted onto chocolate in a manner to deliver a high quality, highresolution image. This is particularly valuable for images withintricate patterns which otherwise might produce lower quality or lowerresolution images.

As mentioned earlier, the surface chemistry of the ink and the chocolatesurface play a critical role in determining the final image quality andresolution. Other embodiments according to the invention which can haveadvantageous effect on image quality include, controlling the surfaceenergy of the chocolate by changing the temperature of the substrate ofthe ink, using a stream of dry gas to assist the rapid drying of inkdroplets on the surface of the chocolate and applying coatings to thechocolate to enhance the compatibility of the chocolate to the ink.

Temperature modulation will affect the surface energy properties of theink and chocolate with lower temperatures lowering surface energy andreducing the tendency of an ink to spread across the chocolate surface.Applying very low humidity gas or air will enhance the drying rate ofthe ink droplets and can be employed effectively with the multi-passprinting embodiment discussed above. Temperature modulation of the inkcartridge can also be advantageously used to modify and or control inkrheology to maximize printing performance.

In some instances it may be desirable to enhance the compatibility ofthe surface of the confection by depositing a thin layer of an ediblebinder or other compatibility-enhancing component prior to the step ofprinting the image. Water-based glazes containing gums and/or cornsyrups and/or oils, and/or acids and/or sugars and/or starches and/orlow-carbon alcohols and/or shellacs and/or other resins providesufficient chocolate surface modification to allow high-resolutionimages to be printed using the above mentioned inks. Solvent basedglazes may also be useful. Commercial names of exemplary water-basedglazes include, without limitation, commercially available Capol 140,Capol 120, Capol 153D, Capol 149 products, available from CenterchemFoods, Stamford, Conn. These ingredients, besides providingcompatibility of inks to chocolate surface, provide a unique glazedappearance to the printed images. Other components which may be coatedon the surface of an edible substrate prior to printing includesurfactants, antibloom agents, micronutrients and flavor enhancers.

An example of a surfactant than can improve the compatibility of the inkwith a chocolate surface is Adsurf 456K. Application of a thin layerimproves the image quality and resolution significantly. Anotherembodiment of the invention involves the application of more than onesurface pre-treatment layer prior to ink-jet printing. Among surfacepre-treatments, the application of a Capol glaze to the chocolatesurface provided the best surface in terms of ink compatibility.However, it is very difficult to deliver a uniform layer of the Capolglaze to the chocolate surface. Surprisingly, it has been found thatcombining a first pre-treatment application of a surfactant, such asAdsurf 456K, followed by a second application of Capol provides a verysignificantly improved surface for ink-jet printing. The sequentialapplication of this multi-layer pre-treatment, using a foam brush,provides a smooth highly compatible surface for edible pigmented ink-jetink. This delivers a very superior image quality and resolution. Thissurface is also much less prone to ink droplet coalescence problems.

The image enhancement techniques discussed in application to chocolateproducts are not limited to these products but are generally applicablein principle to other edible substrates.

The present invention also provides for novel high resolution printededibles wherein the edibles have a substantially planar or substantiallynon-planar shape. As used herein, substantially planar includes, forexample, a chocolate tablet, while substantially non-planar includes,without limitation, an interior or exterior surface having curvature,such as an egg. The novel printed edible is printed on at least onesurface having localized 3-D features if substantially planar. Ifsubstantially non-planar, the printed surface may be on localized 3-Dfeatures. Localized 3-D features can include, without limitation, unevenor irregular surfaces, such as grooves, ridges, pinholes, and the like,as well as embossed or molded designs in the edible substrate.

In preferred embodiments, the edible may be moved or rotated in anappropriate manner to transiently bring a non-planar surface intocorrect position and distance for printing below or aside a drop ondemand printer head. For example, high resolution images can be printedon a Chocolate Easter Egg by a system which holds the egg and moves itpast a horizontally mounted printer head in rotational manner to presentan arc of the egg surface for printing. In a particularly preferredembodiment the system will control the edible in such a manner as totransiently maintain the non-planar surface being printed at aperpendicular angle to the print head.

In another preferred embodiment, it is possible to print the interiorsurface of a ½ egg or ½ ball shaped product produced by shell moldingand which is ultimately joined to another half to yield a hollow moldededible product.

In formulating an ink composition that is edible, ink-jettable, andwhich provides an acceptable high-resolution high quality image, severalcompeting factors need to be addressed. Generally speaking, a dye-basedink will not provide an acceptably high-quality image on most ediblesubstrates, such as dark surfaced substrates and/or non-porousmaterials, due to poor image contrast and therefore, the invention isdirected primarily to dispersed pigmented inks.

The edible dispersed pigmented inks of the invention are generallyprepared in the following manner. First, the pigment dispersion isprepared by thoroughly mixing an edible pigment with a suitable edibledispersant. Next, the pigment dispersion is carefully diluted orlet-down using an edible carrier fluid to produce the dispersedpigmented ink. As the inks of the invention are water based, the carrierfluid will typically be comprised of water and an edible alcohol.Optionally, an edible surfactant may be added to the ink, either at thedispersion step or later.

In preparing dispersed pigmented inks, enough pigment must be used inthe formulation to lend sufficient opacity to the printed image, and itmust be ensured that the pigment is uniformly dispersed in the ink. Inthe production of a white ink, at least about 3 weight percent of whitepigment is required to provide sufficient opacity and dispersivity inthe ink. At the same time, if too much pigment is used, the resultingink will tend to clog the nozzle orifices of an ink-jet printer,particularly a drop-on-demand ink-jet printer. Additionally, at highpigment levels, the ink viscosity is increased to levels such thatflowability of ink within the ink cartridge and nozzles is restricted.Thus, an upper compositional limit for pigment in the edible inkcomposition according to the invention is about 55 weight percent. Wheretitanium dioxide is used as the pigment the desirable range is between10-45 weight percent and the most preferred amount of pigment to use isabout 13-35 weight percent. As used herein “weight percent” meanspercent by weight with respect to the weight of the ink composition,unless specifically stated otherwise.

Powdered materials that may be used as a pigment in the edible inkcomposition according to the invention include, but are not limited to:titanium dioxide, aluminum hydroxide, calcium carbonate, sucrose, andtalc. Titanium dioxide is most preferred.

For use with a drop-on-demand ink-jet system, the pigment particlesshould have a particle size between about 0.1 and about 1.5 microns. Thepreferred titanium dioxide pigments have an average particle size in therange of about 0.2 to about 0.5 microns, with an average particle sizeof 0.3 microns being the most preferred particle size.

To prepare an ink composition according to one embodiment of theinvention, first the pigments are dispersed in a dispersant to producethe pigment dispersion. Suitable dispersants include, withoutlimitation, glycerine and/or propylene glycol and/or polypropyleneglycol and other polyglycerols and polyols. A suitable amount ofglycerine and/or propylene glycol and/or polypropylene glycol and otherpolyglycerols and polyols will serve to adequately disperse the pigmentwhile making sure that fluid properties of the finished ink are notadversely affected. The preferred range of glycerine and/or propyleneglycol and/or polypropylene glycol and other polyglycerols and polyolsin the finished ink is between about 1 percent and about 48 percent.

According to the invention, other dispersants may also be used beyondthose described above. The essential requirements being that thedispersant is edible and effectively disperses the pigment and does notlead to clogging problems of the printer nozzle orifice. For example,water based carbohydrate and or protein solutions may also be used todisperse the pigment. It is also possible to use combinations ofdispersants. It is also possible to use salts or other compounds tocharge the pigmented particles and therefore help disperse the pigments.

The ink compositions according to the invention are typicallywater-based. Preferably, water comprises between about 30 and about 75weight percent of the final ink composition. In yet another embodiment,the ink composition may also be substantially free of water.

An alcohol is added to the ink composition as part of the carrier sothat the image will dry quickly once printed. Any alcohol suitable foruse with an edible composition that will increase the volatility, andtherefore the drying speed, of the ink may be used. Lower alcohols, andin particular ethanol and isopropyl alcohol, are preferred. Enoughalcohol must be used to ensure that the ink will dry quickly, but not somuch that the flashpoint of the ink composition is reduced to adangerous level. The preferred range of alcohol is between about 5 andabout 70 weight percent of the final ink composition. A more preferredrange is between about 7 weight percent and about 45 weight percent. Themost preferred range of alcohol is between about 10 weight percent andabout 25 weight percent with respect to the final ink composition.

The edible ink composition according to the invention may also comprisea surfactant to improve the compatibility of the ink with the surface ofthe chocolate. The surfactants that may be used in the ink of thisinvention include, for example, anionic surfactants, cationicsurfactants and amphoteric surfactants. Of course, the surfactant usedmust be edible in the amounts used. The most preferred surfactants arepolyglycerol oleates, monostearates, polysorbates, mono anddiglycerides, commercially available under the tradenames of Adsurf456K, Tween 60, Tween 80, Span 60, and Span 80, Myverol and Myvecet.Generally, a surfactant will be present in amounts less than about 1.0weight percent. Most preferably, the surfactant will be present in anamount between about 0.001 and about 0.5 weight percent (based on finalink-formulation).

As the composition is an edible composition, a simple composition ispreferred. The edible ink according to preferred embodiments of theinvention is substantially free of shellac or polymeric binder. It hassurprisingly been found that the composition as recited above, with theoptional addition of a small amount of surfactant is sufficient toobtain good image durability and compatibility of the image with achocolate substrate.

Other ingredients may be added to the ink including, but not limited toflavor enhancers and micronutrients. Such components, frequently addedto the surfaces of edibles, particularly confections, would be known toone of ordinary skill in the art and include, without limitation, mint,fruit and vegetable oils, herbal extracts, cinnamon and coffeeflavorings, vanillin and vanilla extracts (natural and artificial), maltflavors, vitamins, minerals, plant phytochemicals, anthocyanins, etc.Although not particularly limited in this regard, it is contemplatedthat these flavor enhancers and micronutrients may be present in anamount between about 0.01 weight percent and about 5 weight percent.Further, the flavor enhancers and micronutrients added according to theinvention may be suitable for either human or animal palatability andhealth.

As noted earlier, the use of dyes on most edible substrates does notproduce a satisfactory image. However, the ink composition of thepresent invention may include dyes in addition to the pigment. It hassurprisingly been found that combining dyes with titanium dioxidepigment yields colored inks having greater intensity and opacity thanwhen the food dyes are used as sole colorants in an ink formulation. Itis also within the scope of the invention to use lakes in combinationwith titanium dioxide pigment in a colored ink composition.

Generally, if dyes are present, the amount will range between about 0.5and 5.0 weight percent with respect to the edible ink composition. Waterbased dyes such as F D & C approved colors, natural colorants andmica-based metallic color pigments are preferred for use with the edibleinks of the invention.

A consumer-driven, customizable process for producing edibles havingindividualized, high-resolution images printed thereon is made possibleby the invention. The full scope of the invention is set forth in theappended claims, and includes equivalents and alternatives of thedisclosed inks, processes, and systems and obvious variants thereof.

We claim:
 1. An edible, ink-jettable, dispersed pigmented inkcomposition comprising: (a) at least 3% by weight of a dispersedfood-grade white pigment selected from the group consisting of titaniumdioxide, aluminum hydroxide, calcium carbonate and talc; (b) an edibledispersant; (c) an edible alcohol; and (d) water, wherein said inkcomposition is free of shellac and polymeric binder and is ink-jettablethrough a drop-on-demand ink-jet system.
 2. An edible ink compositionaccording to claim 1, wherein said ink is capable of forming an imagehaving a resolution greater than about 200 dpi using a singledrop-on-demand ink jet printhead and single pass printing.
 3. An edibleink composition according to claim 1, further comprising an ediblesurfactant.
 4. An edible ink composition according to claim 1, whereinsaid edible dispersant is selected from the group consisting ofglycerine, propylene glycol, polypropylene glycol, and mixtures thereof.5. An edible ink composition according to claim 4, wherein said edibledispersant is glycerine.
 6. An edible ink composition according to claim4 wherein said food-grade white pigment is present in an amount of about3 to about 55 percent by weight; said edible dispersant is present in anamount of about 1 to about 48 percent by weight; said edible alcohol ispresent in an amount of about 5 to about 70 percent by weight; and saidwater is present in an amount of about 30 to about 75 percent by weight.7. An edible ink composition according to claim 6, further comprising anedible surfactant in an amount of less than about 1 weight percent. 8.An edible ink composition according to claim 4, wherein said ink is afood-grade ink consisting essentially of: titanium dioxide; an edibledispersant selected from the group consisting of glycerine, propyleneglycol, polypropylene glycol, and mixtures thereof; an edible loweralcohol, and water.
 9. An edible ink composition according to claim 8,wherein said titanium dioxide is present in an amount of about 10 toabout 45 percent by weight; said edible dispersant is present in anamount of about 1 to about 48 percent by weight; said edible loweralcohol is present in an amount of about 5 to about 70 percent byweight; and said water is present in an amount of about 30 to about 75percent by weight.
 10. An edible ink composition according to claim 4,wherein said ink is a food-grade ink consisting essentially of: titaniumdioxide; an edible dispersant selected from the group consisting ofglycerine, propylene glycol, polypropylene glycol, and mixtures thereof;an edible lower alcohol; water, and an edible surfactant.
 11. An edibleink composition according to claim 10, wherein said titanium dioxide ispresent in an amount of about 10 to about 45 percent by weight; saidedible dispersant is present in an amount of about 1 to about 48 percentby weight; said edible lower alcohol is present in an amount of about 5to about 70 percent by weight; said water is present in an amount ofabout 30 to about 75 percent by weight; and said edible surfactant ispresent in an amount of less than about 1 weight percent.
 12. An edibleink composition according to claim 11, wherein said edible surfactant ispresent in an amount of about 0.001 to about 0.5 weight percent.
 13. Anedible product comprising a high resolution image formed from adispersed pigment food-grade ink according to claim 1 on at least onesurface of an edible substrate.
 14. An edible product according to claim13, wherein said edible substrate is a confectionery product, cookie,starch-based savory snack, pet food, or ice cream.
 15. An edible productaccording to claim 14, wherein said edible substrate is dark chocolate,milk chocolate, white chocolate, a sugar shell product or hard candy.16. An edible dispersed pigmented ink composition comprising: (a) atleast 3% by weight of a dispersed food-grade white pigment selected fromthe group consisting of titanium dioxide, aluminum hydroxide, calciumcarbonate and talc; (b) an edible dispersant; (c) an edible alcohol; and(d) water, wherein said ink composition is free of shellac and polymericbinder.
 17. An edible ink composition according to claim 16, furthercomprising an edible surfactant.
 18. An edible ink composition accordingto claim 16, wherein said edible dispersant is selected from the groupconsisting of glycerine, propylene glycol, polypropylene glycol, andmixtures thereof.
 19. An edible ink composition according to claim 18,wherein said edible dispersant is glycerine.
 20. An edible inkcomposition according to claim 16 wherein said food-grade white pigmentis present in an amount of about 3 to about 55 percent by weight; saidedible dispersant is present in an amount of about 1 to about 48 percentby weight; said edible alcohol is present in an amount of about 5 toabout 70 percent by weight; and said water is present in an amount ofabout 30 to about 75 percent by weight.